Wrapping machine

Abstract: A wrapping machine (10) comprises a ring (16) rotatable on a frame (12), a ledge (20) to support a package (P) being wrapped, and a carriage (30) supporting a roll (R) of plastic film (F) and movable with the ring (16) to wrap the film (F) around the ledge (20) and around a package (P) supported by it. A severing arm (70) is pivotable between a horizontal position underlying the ledge (20) and a vertical position and carried a heated severing wire (72). Also, a spacing arm (60) is pivotably movable between a horizontal position underlying the ledge (20) and a vertical position and spaces an outer film layer from the ledge (20). In one embodiment, the severing arm (70) carries heated welding elements (74), and the spacing arm (60) applies a partial vacuum to cause a severed film portion (F) to adhere to it. In another embodiment, the severed film portion is clamped between the spacing (100) and severing (110) arms (Figure 9).

Description: This invention pertains to a film-severing mechanism useful in a machine for wrapping a package with plastic film supplied on a roll. The mechanism is arranged to space a portion of an outer film layer from the next prior film layer and to sever the spaced portion along a generally straight line. The mechanism may be also arranged to weld a portion of the severed film layer to and across the next prior film layer and to remove another portion of the severed film layer. A machine of a type in widespread use for wrapping packages with plastic film supplied on a roll, such as stretch film, comprises a frame, a ring rotatable on the frame and defining a circular path around a horizontal axis, a support extending horizontally toward an open centre of the ring and arranged to support a package being wrapped, and a carriage mounted to the ring for conjoint movement with the ring and arranged to support the roll of film with its axis parallel to the horizontal axis of the ring. The support may be a ledge or a conveyor. The carriage is movable along the circular path, around the ledge, when the ring is rotated so that film from the roll supported by the carriage is wrapped in successive layers, around the support and around a package supported by the support, as the carriage is moved around the ring. A leading edge of the film is secured to the package, as by taping, before the film is wrapped therearound. After the support and the package supported by the support have been wrapped with plural layers of the film, the wrapped film is severed from the film remaining on the roll, and an outer layer of the wrapped film is secured to the next prior layer of the wrapped film, commonly by welding or taping. Such wrapping machines are available commercially, as "MSB Stretch Bundlers", from ITW Mima (a unit of Illinois Tool Works Inc.) of Boca Raton, Florida. Manual machines are known, in which the carriage is moved manually along the circular path defined by the ring. Powered machines are known, in which the carriage is moved by a motor. In a wrapping machine of the type noted above, as known heretofore, the film of the outer layer is bunched into a rope-like configuration when such film is severed from the film remaining on the roll. Generally, the rope-like configuration is retained when the outer layer is secured to the next prior layer, particularly if welding or taping is used. Such a rope-like configuration can interfere with stacking or palletizing of the package with other packages. Also, such a rope-like configuration may lend an unsatisfactory appearance to a package, particularly if the package is placed into a retail store without removal of the film wrapping the package. There has been a need, to which this invention is addressed, for a better way to sever the film of the outer layer from the film remaining on the roll. US-A-4,761,934 discloses a clamp suitable for holding and cutting a plastics film used for wrapping a package. The clamp includes a first elongate clamping member which extends across one surface of the film to be clamped, and a second elongate clamping member which is extended across the opposite surface of the film to cut the film and clamp the film between the clamping members. A further clamp for holding and cutting a plastic film is known from GB-A-2 150 523. According to this invention a mechanism for use with a machine for wrapping a package with plastic film supplied on a roll the machine including a support for supporting the package being wrapped, the support being wrapped with the package, the mechanism being arranged to sever an outer layer of such film from a next prior layer of such film wrapped around the support and the package, the mechanism comprising: spacing means for spacing a portion of the outer film layer from the next prior film layer wrapped around the support and around the package wherein the spacing means comprises a spacing arm mounted so as to be movable pivotably between a first horizontal position, in which the spacing arm underlies the support with any prior film layer being confined between the spacing arm and the support and in which the spacing arm is disposed to be also wrapped by the outer film layer and to space a portion of the outer film layer from the next prior film layer, and a second position, in which the spacing arm does not interfere with film being wound around the support and around the package; and, severing means for severing the outer film layer at the spaced portion along a generally straight line extending across the spaced portion, into a first portion integral with film wrapped around the support and around the package and a second portion integral with film on the roll, in which the spacing means and severing means are provided beside each other, and the film is severed between the spacing means and the severing means. Preferably, moreover, the wrapping machine comprises means for welding the first portion of the severed film layer to the next prior film layer and means for removing the second portion of the severed film layer from the wrapped support and from the wrapped package supported by the support. In the preferred embodiment, a severing and welding arm is mounted so as to be pivotally movable between a generally horizontal position, in which the severing and welding arm underlies the support with the outer film layer between the severing and welding arm and the support, and a generally vertical position, in which the severing and welding arm does not interfere with film being wound around the support and around a package supported by the support. Moreover, in the preferred embodiment, the severing and welding arm carries a heated wire constituting means for severing the spaced portion of the outer film layer into a first portion integral with film wrapped around the support and around a package supported by the support and a second portion integral with film on the roll. Furthermore, in the preferred embodiment, the severing and welding arm carries other heated elements constituting means for welding the first portion of the severed film layer to and across the next prior film layer. Additionally, in the preferred embodiment, a fixed wall is disposed to enable the spacing and removing arm to clamp the second portion of the severed film layer against the fixed wall when the spacing and removing arm with the second portion adhering thereto is pivoted from the horizontal position to the vertical position. As a further feature of the preferred embodiment, the spacing and removing arm comprises means for applying a partial vacuum to the second portion of the severed film layer so as to cause the second portion of the severed film layer to adhere to the spacing and severing arm as the spacing and severing arm is pivoted from the horizontal position to the vertical position. A preferred embodiment of a wrapping machine in accordance with this invention will now be described with reference to the accompanying drawings; in which:- Figure 1 is a fragmentary, perspective view of the wrapping machine; Figure 2 is a fragmentary, schematic, elevation drawn to an enlarged scale showing the film being wrapped around the ledge and package; and, Figures 3, 4, 5, and 6 are fragmentary, schematic, perspective views showing successive stages in the operation of the preferred embodiment. As shown in the Figures, machine 10 for wrapping a package P with plastic film F supplied on a roll R defining a roll axis constitutes a preferred embodiment of this invention. As shown, the package P is comprised of nine elongate boxes B stacked in three rows and three columns. Preferably, the film F is stretch film, which is available commercially from many sources including ITW Mima, supra. As shown fragmentarily, the machine 10 comprises a frame 12 mounting grooved rollers 14 and a ring 16, which is mounted rotatably to the frame 12 via the rollers 14 in a known manner. The ring 16 defines a ring axis, which is horizontal. Also, the ring 16 defines a circular path and has an open centre. Further, the machine 10 comprises a ledge 20, which is fixed to the frame 12 in a known manner. The ledge 20 extends horizontally toward and through the open centre of the ring 16 and is arranged to support the package P being wrapped. Moreover, the machine 10 comprises a carriage 30, which is mounted fixedly to the ring 16 so that the carriage 30 is moved along the circular path, around the ledge 16, when the ring 16 is rotated about the ring axis. The carriage 30 may be so moved via a motor (not shown) in a known manner or manually. The carriage 30 is arranged to support the roll R, via a spindle 32 extending from the carriage 30 and permitting the roll R to rotate on the roll axis, with the roll axis parallel to the ring axis. The carriage 30 mounts a prestretching mechanism 34 of a known type (see, e.g., Lancaster et al. U.S. Patent No. 4,302,920) which mechanism 34 is used to prestretch the film F as the film F is unwound from the roll R. A leading edge of the film F is pulled from the roll R, through the prestretching mechanism 34, and is secured to the package P supported on the ledge 20, as by taping. Next, the ring 16 and the carriage 30 are rotated in a direction indicated by a curved arrow in Figure 1, so as to wrap the film F in successive layers around the ledge 20 and around the package P supported by the ledge 20. Next, an outer layer of the film F is severed from the film F remaining on the roll R, whereupon a trailing end of the outer layer is secured to the package P, as by welding or taping the trailing end to the next prior layer of the film F wrapped therearound. Finally, the wrapped package P is pushed from the ledge 20, as by a similar package P' to be next wrapped. As described so far, the machine 10 is conventional and is similar to one of the "MSB Stretch Bundlers" available commercially from ITW Mima, supra. Broadly, the operation of the machine 10 is similar to the operation of the same "MSB Stretch Bundlers". However, the machine 10 comprises novel means described below for spacing a portion 40 of an outer layer 42 of the film F from the next prior layer 44 of the film F wrapped around the ledge 20 and around the package P supported by the ledge 20, for severing the outer layer 42 at the spaced portion 40, along a generally straight line extending across the spaced portion 40, into a first portion 46 integral with the film F wrapped therearound and a second portion 48 integral with the film F remaining on the roll R, for welding the first portion 46 to and across the next prior layer 44, and for removing the second portion 48 from the ledge 20 and from the package P supported by the ledge 20. The spacing and removing means comprise a spacing and removing arm 60 mounted pivotably to the frame 12, via a pivot pin 62, so as to be pivotable between a generally horizontal position and a generally vertical position. A pneumatic or otherwise powered mechanism (not shown) is provided for pivoting the arm 60 selectively between the generally horizontal and generally vertical positions. For a purpose to be later described, the arm 60 has two elongate cavities 64 opening at one planar surface 66 of the arm 60, which surface 66 faces downwardly when the arm 60 is pivoted to the generally horizontal position. The elongate cavities 62 communicate with a vacuum line V (see Figure 2) which is connected to a vacuum pump (not shown) or other known means for applying a partial vacuum. In the generally horizontal position, in which the arm 60 is shown in solid lines in Figures 2, 3, and 4, the arm 60 underlies the ledge 20 with any prior film layer being confined between the arm 60 and the ledge 20. In the generally horizontal position, the arm 60 is disposed to be also wrapped by the outer layer 42 of the film F and to space the aforenoted portion 40 of the outer layer 42 from the next prior layer 44 of the film F, generally as shown in Figure 3. In the generally vertical position, in which the arm 60 is shown in solid lines in Figures 1 and 6, the arm 60 does not interfere with the film F being wound around the ledge 20 and around the package P supported by the ledge 20. The severing and welding means comprise a severing and welding arm 70 mounted pivotably to the frame 12, via the pivot pin 62 used to mount the arm 60, 80 as to be pivotable between a generally horizontal position and a generally vertical position. A pneumatic or otherwise powered mechanism (not shown) is provided for pivoting the arm 70 selectively between the generally horizontal and generally vertical positions. The arm 70 carries a severing wire 72, which is arranged to be electrically heated in a known manner, and an array of welding elements 74, which are arranged to be similarly heated. In the generally vertical position, in which the arm 70 is shown in Figures 1, 3, and 6, the arm 70 does not interfere with the film F being wound around the ledge 20 and around the package P supported by the ledge 20. The severing wire 72 is carried along one side 76 of the arm 70 so as to extend across the spaced portion 40 of the outer layer 42 of the film F, after such portion 40 has been spaced from the next prior layer 44 of the film F by the arm 60, when the arm 70 is pivoted from the generally vertical position to the generally horizontal position. When the severing wire 72 engages the spaced portion 40, the severing wire 70 is heated so as to sever the outer layer 42 at the spaced portion 40 into the first portion 46 integral with the film F wrapped around the ledge 20 and around the package P supported by the ledge 20 and the second portion 48 integral with the film F remaining on the roll R. The welding elements 74 are carried by the arm 70 so as to extend along one planar surface 78 of the arm 70, which surface 78 faces upwardly when the arm 70 is pivoted to the generally horizontal position. The welding elements 74 are covered by a thin layer of a protective material, which preferably is polytetrafluoroethylene (PTFE) tape. When the arm 70 is pivoted to the generally horizontal position, the welding elements 74 are heated so as to weld the first portion 46 of the severed outer layer 42 of the film F to and across the next prior layer 44 of the film F, as the arm 70 presses the first portion 46 of the film F against the next prior layer 44 of the film F. When the outer layer 42 of the film F is severed by the severing wire 70, a partial vacuum is applied to the elongate cavities 62 of the arm 60, via the vacuum line V, so as to cause the second portion 48 of the severed outer layer 42 to adhere to the arm 60. Thereupon, as shown in Figure 5, the arm 60 is pivoted from the generally horizontal position to the generally vertical position with the second portion 48 continuing to adhere to the arm 60 because of the partial vacuum. The machine 10 comprises a wall 80 fixed to the frame 12. The wall 80 is disposed to enable the arm 60 to clamp the second portion 48 of the severed outer layer 42 of the film F against the wall 80 when the arm 60 with the second portion 48 adhering thereto is pivoted from the generally horizontal position to the generally vertical position. After the outer layer 42 of the film F has been severed and the first portion 46 of the severed outer layer 42 has been welded to the next prior layer 44, the arm 70 is pivoted from the generally horizontal position to the generally vertical position. Another package P' similar to the wrapped package P may be then pushed onto the ledge 20 so as to displace the wrapped package P, which may be thus stripped from the ledge 20. The film portion 48 clamped between the arm 60 and the wall 80 may be then released 80 as to provide the leading edge of the film F to be then used to wrap the package P' in a similar manner.

Claims: A mechanism for use with a machine for wrapping a package (P) with plastic film (F) supplied on a roll (R), the machine including a support (20) for supporting a package (P) being wrapped the support being wrapped with the package, in which the mechanism is arranged to sever an outer layer of such film (F) from a next prior layer of such film (F) wrapped around the support (20) and the package (P), the mechanism comprising: (a) spacing means (60,100) for spacing a portion of the outer film layer (F) from the next prior film layer wrapped around the support (20) and around the package (P), wherein the spacing means comprises a spacing arm (60,100) mounted so as to be movable pivotably between a first horizontal position, in which the spacing arm (60,100) underlies the support (20) with any prior film layer being confined between the spacing arm (60,100) and the support (20) and in which the spacing arm (60,100) is disposed to be also wrapped by the outer film layer and to space a portion of the outer film layer from the next prior film layer, and a second position, in which the spacing arm (60,100) does not interfere with film (F) being wound around the support (20) and around the package (P) and, (b) severing means (72,134) for severing the outer film layer at the spaced portion along a generally straight line extending across the spaced portion, into a first portion integral with film (F) wrapped around the support (20) and around the package (P) and a second portion integral with film (F) on the roll (R), in which the spacing means (60,100) and severing means (72,134) are provided beside each other, and the film (F) is severed between the spacing means (60,100) and the severing means (72, 134). A mechanism according to claim 1, in which the second position is a generally vertical position. The mechanism of claim 1 or 2, further comprising: (c) means for removing the second portion of the severed film layer (F) from the wrapped support and from the wrapped package. The mechanism according to any one of the preceding claims further comprising means for welding the first portion of the severed film layer to and across the next prior film layer. The mechanism of any preceding claim wherein the severing means comprises a severing arm (70,100) mounted so as to be pivotably movable between a generally horizontal position, in which the severing arm (70,100) underlies the support (20) with the outer film layer between the severing arm and the support (20), and a generally vertical position, in which the severing arm (70,100) does not interfere with film being wound around the support (20) and around the package (P) the severing arm (70,100) carrying a heated wire (72,134) arranged to sever the outer film layer. The mechanism according to claim 3, or any one of claims 4 or 5 when dependent on claim 3, wherein the removing means comprises a spacing and removing arm (60) mounted so as to be pivotably movable between a generally horizontal position, in which the spacing and removing arm (60) underlies the support (20) with any prior film layer being confined between the spacing and removing arm (60) and the support (20) and in which the spacing arm is disposed to be also wrapped by the outer film layer and to space a portion of the outer film layer from the next prior film layer, and a generally vertical position, in which the spacing and removing arm does not interfere with film being wound around the support and around the package, the spacing and removing arm comprising means (64) for applying a partial vacuum to the second portion of the severed film layer (F) so as to cause the second portion of the severed film layer to adhere to the spacing and severing arm (60) as the spacing and severing arm is pivoted from the generally horizontal position to the generally vertical position. The mechanism of claim 6, further comprising a fixed wall (80) disposed to enable the spacing and removing arm (60) to clamp the second portion of the severed film layer against the fixed wall (80) when the spacing and removing arm (60) with the second portion adhering thereto is pivoted from the generally horizontal position to the generally vertical position. The mechanism of claim 5 when dependent upon claim 4, wherein the welding means comprises a severing and welding arm (70) mounted so as to be pivotably movable between a generally horizontal position, in which the severing and welding arm (70) underlies the support (20) with the outer film layer between the severing and welding arm (70) and the support, and a generally vertical position, in which the severing and welding arm (70) does not interfere with film (F) being wound around the support (20) and around the package (P), the severing and welding arm (70) carrying a heated wire (72) arranged to sever the outer film layer and carrying other heated elements arranged to weld the first portion of the severed film layer to and across the next prior film layer. A machine (10) for wrapping a package (P) with plastic film (F) supplied on a roll, the machine comprising a support (20) for supporting a package (P) to be wrapped, a mechanism (14,16,30) for wrapping the film around the package (P), and a mechanism in accordance with any one of the preceding claims.

Inventors: SCHERER PHILIP G, SCHERER, PHILIP G.
Applicants: MIMA INC, MIMA INCORPORATED
Application year: 1994
Main classification: B65B11
IPC codes: B65B11, B65B13